The goal of this project is to develop a new technique for cross-sectional imaging of the mandibular body before dental implant insertion. The approach is based on reconstruction of a binary pattern from two x-ray projections by employing a combinatorial reconstruction algorithm. The short-term specific aims are intended to justify the in vitro applications of this technique. Aim I. To perform a simulation study to determine at which x-ray energies there is sufficient contrast between bone and soft tissue for the mandible to be considered a binary object. Aim II. a) To simulate a cross-sectional image of the mandibular body as an oval with a hole resembling the mandibular canal, using a higher resolution 200 x 200 matrix, and to test whether a similar pattern can be reconstructed from two orthogonal projections of an oval construct. b) To simulate the cross-section with a more complicated pattern and perform reconstruction. Aim III. To test the technique using a practical dental x-ray device that has several non-ideal properties including nonparallel rays, polyenergetic x-ray spectrum, the heel effect, slightly different exposures, and possibly nonuniform detector response. b) To determine the magnitude of the errors resulting from these non-ideal properties and, where possible, develop and implement corrections. Preliminary study indicated that the reconstruction algorithm can reconstruct a similar pattern. The long-term goal is to use the techniques developed to acquire cross-sectional image of the mandibular body in dental practice before insertion of dental implants.